1-methyl-4-amino-n&#39;-phenyl-n&#39;-thenyl-piperidines



United States Patent f 1-METHYL-4-AMINO-N'-PHENYL-N'-THENYL- PIPERIDINES Arthur Stoll, Arlesheim, near Basel, and Jean-Pierre Bourquin, Basel, Switzerland, assignors to Sandoz A. G., Basel, Switzerland No Drawing. Application November 26, 1952,

Serial No. 322,792

Claims priority, application Switzerland November 30, 1951 4 Claims. (cl. 260-2934;

The present invention is concerned with valuable lmethyl-4-amino-N'-phenyl-N-thenyl-piperidines.

More particularly, theinvention is concerned with piperidine derivatives which correspond to the type formula:

1 CH3 I wherein X represents one of the following moieties These piperidine derivatives are valuable pharmaceuti cally, being characterized by excellent antihistaminic activity and by low toxicity and good compatibility (freedom from undesired side reactions). They may be administered, for example, orally.

The said piperidine derivatives are prepared, according to the present invention, by reacting a compound of the formula:

N v 41H: II with a halide of the formula 2,717,251 Patented Sept. 6,1955

Xhal is then added to the resultant mixture which is allowed to remain at room temperature until theyensuing con; densation is completed or is heated to an'elevated temperature for thispurpose. Upon completion otthe condensation, the reaction product is'added toia suitable organic solvent and, after suitable working up; is'distilled under reduced pressure. If further purification of the thus-obtained product is desired, this can be realized by converting theproduct into a suitable salt and then recovering the compound from the latter.

The compounds of Formula II-may be prepared by reacting the correspondingcompounds of the formula with aniline in the presence ofa condensationcatalyst, and then catalytically reducing the thus-obtainedproduct (Schitfs base)... Thus, for example, 1-methyl-4-amino N'-phenyl-piperidine can be prepared by condensing 1- methyl-4-piperidone with aniline in the presence, as con t solely illustrative and not at all limitative of the inven tion, set forth representative exemplary embodiments. of the latter. In these examples, the temperatures are ex pressed in degreescentigrade. The relationship between part by weight and part by volume is the same as that which exists between the gram and the cubic centimeter-i -Example 1- 190.12 parts by weight of l-methyl-,4-amino-N'-phenylpiperidineare dissolved in thefiveto six-fold quantity of absolute xylene and then, while refluxing and stirring the resultant solution, 42.92 parts by weight of sodamide (10% excess) are added in the course of .2 to 3 hours; Then, without interrupting the heating, 144.5 parts by weight of freshly distilled 2-thenyl chloride, dissolved in the two-fold quantity of absolute xylene, are added drop wise in the course of 1% hours, the mixture being thereupon heated for 40 to 42 hours at an oil-bath temperature of After the'mixture has cooled, any sod'amide which is present is decomposed with 10 to 20 parts by weight of NHiCl, xylene is added, and the mixture shaken out with about 600 parts by volume of water. The aqueous extract is clarifiedby filtration and then shaken out with benzene. The xylene and, benzene extracts are concentrated by evaporation under reduced pressure, any remaining unreacted Z-thenyl chloride removed at a pressure of 11 mm. and at an oil-bath temperature of 110, and the residue from the evaporation then distilled at a pressure of 0.1 mm. Unreacted 1- methyl-4- amino-N'- phenyl-piperidine distils over first at 110-120, followed by impure 1-methyl-4-amino-N- phenyl-N'-(2-thenyl)-piperidine I at -190". H.

is recrystallized from the 17-fold quantity (by volume} of absolute alcohol,- with addition of animal charcoal, followed by recr stallization train the 16-fold quantit (by r ot-time) of a mixture ot? alcohol andbeniene (1 :1). The purified mono-oxalate melts at 160-4-62" (decomposition).

To obtain the pure ba'se', theox-alate' is dissolved at about '40' in the twenty to thir'ty fold quantity (by volume) of water and, while cooling with ice-water, the solution is rendered alkaline with 3-normal aqueous NaOH solution. The base,- which at first separates in the form of a milky precipitate, crystallizes in the course of several hours and is then recrystallized from the 12- fold quantity (by volume) of an alcohol-water mixture (7.5:4.5). The purified base melts at 95-97".

In manner analogous to thattor the preparation of tire none-oxalate, the di hydro chloridejof the l niethyl- =Np1ieiiyn-N (genen n-pipeiidine can also be iniiumo prepared. It melts at 228=231 (decomposition).

Example 2 ssfiparts by weig'ht' or 1 methyl 4-atitifio-N'-pheriyl fsiperidine are dissolved are ten-fold qu ntit of absolute xylene and, after the addition of 19.0 airs by weight of sodariii'de (10% excess) to the resultant solutiei the latter is boiled tinder reflux for 2 to 3 hours, in "'ng. The reaction mixture is cooled to room j (26-30) after which, in the course or 1 /1 treats, 7525s par s by weight or nanny distilled S -chiofdii-ttieiiyt euro as boiling tidiiit GG-Gii at 0.5 pressur dissolved in the three-fold quantity of abse= tute'xytefie, are addederepwise. Tner'eiipen the mixture is heated to 170 for 40 42 hours. After the mixtitre has cooled, any sodarnide which is present is decomposed with 10-20 parts by weight of ammonium chloride, x-ylene is added, and the mixture is shaken out 3 titties, each time with about 200 parts by volume of water.- The clear aqueous solution is shaken out with benzene.- The xyiene and benzene extracts are concentrated by evapratio'n under reduced pressure,- the rest of the solvent evaporated at 11 mm; pressure, and the residue from the evaporation then distilled at a pressure of mm: Unreacted 1-ri1ethyl 4-amino-N-phenyl pipridine distiIs over first at 110-120 followed by impure l'- l"rit'etliyl 4 amino N -,chloro 2 tlienyl) N' piienyl-piperidiriei f5 Inc. on,

a it:

In order to purify the latter compound, the latter distillate is dissolved in the five-fold quantity of absolute alcohol and to the resultant solution, alcoholic hydrochloricl acid of 40% strength is added until an acid reaction to Congo is achieved. A mixture of monoand di-hyd rochloride crystallizes'out and this is dissolved in the ten-fold quantity of water, after which the resultant solution is adjusted with three-normal caustic soda solution to alkalinity toward phenol-phthalein. The crude base which precipitates and which has a melting point of 92=94 is dissolved in the twentyold quantity of abso lute alcohol, after which the equivalent quantity ofan alcoholic tartaric acid solution is added. The tartrate which crystallizes out is recrystallized from the fifteenfold 'quantity of absolute alcohol. The thus-obtained pure tartrate of l-methyl-4-a'mino-N'-(5-chloro-2-thenyl)- N'-phenyl-piperidine has a melting point of 148-l 50.

The pure base is prepared from the tartrate' by' dissolving' the latter in the ten-fold quantity of water and then adjusting to alkalinity by means of 3-normal caustic soda. The thus-precipitated base is recrystallized from the seven-fold quantity of aqueous alcohol The thus-purified base melts at 9294.

Example 3 81.5 parts by weight of 1-methyl-4-amino-N'-phenylpiperidine are dissolved in the ten-fold quantity of absolute xylene and the resultant solution, after the addition of 18.3 parts by weight of sodaniide (10% excess), boiled under reflux, while stirring. Thereupon the reaction mixture is cooled to room temperature (20 30) and 96.4 parts by Weight of S-bromo-Z-thenyl-chloride (boiling point=5864 at 0.1 mm.) dissolved in the 4 /2-fold quantity of absolute xylene, are added dropwise in the course of 1 /2 hours. Heating is continued at 170 for 40-42 hours. After the mixture has cooled, any sodamide which may be present is decomposed with 20 parts by weight of ammonium chloride, xylene is added, and the mixture shaken out 3 times, each time with about 200 parts by volume of water. The clear aqueous solution is extracted with benzene. The xylene and benzene extracts are concentrated by evaporation under reduced pressure, residual xylene and 5-bromo-2-thenyl-chloride distilled off at 11 mm. pressure and at a temperature of 130, and the residue from the evaporation then distilled at a pressure of 0.1 mm. Unreacted 1-methyl-4-arnino-N-phenylpiperidine distils over first at I10l20 followed by impure 1- methyl 4 amino N (5 bromo 2 thenyl) N' phenyl-piperidine at l-215.

In order to purify the latter compound, the last-mentioned distillate is recrystallized from the four-fold quantity of absolute alcohol to which animal charcoal has been added, whereupon the base crystallizes out. The latter is recrystallized from the nine-fold quantity of absolute alcohol. The thus-purified base has a melting point of 138-142.

The tartrate is prepared by dissolving the base in the twenty-fold quantity of absolute alcohol, followed by the addition to the resultant solution, of the equivalent quantity of an alcoholic tartaric acid solution. The precipitated crystalline substance is again recrystallized from the for't'y'= fold quantity of absolute alcohol; the thus-obtained tartrate of l-methyl-4-amino-N'-(S-bromoQ-thenyl)N- phenyl-piperidine has a melting point of 159-162".

Example 4 102 parts by weight of 1-rnethyl-4-amino=N'-(p rnethyl phenyD-piperidine are dissolved in the tenfold quantity of abseliitexylene and then, after the addition of 21.4 parts by weight or seaamide (19% excess), the solution is boiled under reflux for 2 to 3 hoe swhne stirring. Then, without interrupting the heating, 75.4 parts by' weight'of 'z-nienyl chloride (boiling point=70-75 11 min.) dissolved in the four-fold quantity of absolute xylene, are added dropwise in the course of 1 hours, after which heating is continued for 48 hours at 170. After the mixture has cooled any sodamide which is present is decomposed by 20 parts by weight of ammonium chloride, xylene is added, and the mixture shaken out 3 times, each time with 200 parts by volume of water. The clear aqueous solution is extracted with benzene. The xylene and benzene extracts are concentrated by evaporating under reduced pressure. Residual xylene is distilled ofi at a pressure of 11 mm. and a temperature of 130, and the residue from the evaporation then distilled at a pressure of 0.1 mm. Unreacted 1-methyl-4-amino-N'-(p-methylphenyl) -piperidine distils over first at 110135, followed by impure 1-methyl-4-amino-N'-thenyl-N'-(p-methylphenyl)-piperidine (I; S 5 H CH1 In order to purify the latter compound, the last mentioned distillate is dissolved in the eight-fold quantity of absolute alcohol, after which there is added to the resultant solution, the equivalent quantity of an alcoholic oxalic acid solution. The oxalate of 1-methyl-4-amino-N-2- thenyl-N-(p-methyl-phenyl)-piperidine crystallizes out; it has a melting point of 132-135. After recrystallization from the fifteen-fold quantity of absolute alcohol, the oxalate melts at 143-145 In order to prepare the pure base, the oxalate is dissolved in the twenty-fold quantity of lukewarm water and, while cooling with ice, the solution is adjusted by means of 3-normal caustic soda solution to an alkaline reaction to phenolphthalein. The oil base cannot be converted to crystalline form. It is dissolved in benzene, the resultant solution dried and, after evaporating off the benzene, is again distilled under high vacuum. The thus-obtained pure base has a boiling point of at a pressure of 0.4 mm. The yellowish viscous oil does not solidify, even when stored in a refrigerator.

Having thus disclosed the invention, what is claimed is:

1. A- member selected from the group consisting of compounds which correspond to the type formula and salts thereof with acids, wherein X is a member selected from the group consisting of 2. 1-methyl-4-amino-N phenyl-N'-(2 thenyl)-piperidine.

3. 1-methyl-4-amino-N' -(5-chloro-2-thenyl)-N'-phenylpiperidine.

4. 1-methyl-4-arnino-N'-(5-bromo-2-thenyl)-N-phenylpiperidine.

References Cited in the file of this patent UNITED STATES PATENTS Weston June 12, 1951 OTHER REFERENCES 7 Auterhofi: Chem. Abstr., vol. 45, col. 10,490 (1951). 

1. A MEMBER SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS WHICH CORRESPOND TO THE TYPE FORMULA 